1. Field of the Invention
The present invention relates to a method and apparatus for coal mining, and more particularly, relates to a method and apparatus which would provide an improved strip mining method, reducing the land surface and overburden disturbed thereby compared to the conventional strip mining method.
2. General Background and Prior Art
It is a known fact in strip mining of coal, that because of the present methods in strip mining, the land mined thereby is reduced to a non-usable state, in all cases being stripped completely of any vegetation, and the result being massive cuts into the surface of the land which is very unsightly, unable to support any type of vegetation or animal growth, and, susceptible to allowing rain water to run off, thus, increasing the likelihood of flooding and erosion in the area around the strip mining. Also, the present method of strip mining requires the complete removal of topsoil and overburden across the face of the mined land, and very inefficiently collects the coal from the stripped surface, placing it in haulers for hauling out of the area. In terms of the time and great costs of the massive machinery for overburden removal measured against the amount of coal contained in this present method, improvements are very vital, especially in the present energy crisis, coal is being looked upon as the most promising alternative source to the oil and gas crisis, and it is imperative that the method of mining same be made more efficient, coupled with the ability to render the land where the coal has been mined, less detrimentally effected by said mining.
In the present state of the art, several patents have been obtained in regard to mining coal. However, very few patents have been obtained in the art that deals specifically with exterior strip mining in coal. For example, U.S. Pat. No. 4,014,574, entitled "Mining Machine Having Rectangular Thrusts Transmitting Conveyor Column", issued to R. E. Todd, this patent would teach the use of a mining machine having a laterally elongated cutting head means for cutting an earth formation, in laterally elongating thrusts transmitting column connected to and extending rearwardly from the cutting head, and a power head connecting to the rear of the column. It should be noted that the method would depend on the roof of the hole being supported by pillars and a bridging effect. Also, it should be noted that the use of this machine is via screw augers for removing coal, and the power head as shown in the patent, lacks the maneuverability of the free crawler to reposition for the next boring.
Also, in the present state of the art for auger methods of strip mining coal, the augers are used only for that portion of the coal bed unavailable to conventional strip mining methods, due to excessive overburden depth, thus being utilized primarily for closing out an operation.